Cable-cutting apparatus



R. S. BAKER Jan. 2, 1968 CABLE-CUTTING APPARATUS 4 Sheets-Sheet 1Original Filed Feb. 11, 1964 iil R. S. BAKER CABLECUTTING APPARATUS Jan.2, 1968 Original Filed Feb. 11. 1964 4 Sheets-Sheet 2 'iililililili'lilflililili Ell illlilllillli Jan. 2, 1968 R. s. BAKER 3,361,020

CABLECUTTING APPARATUS Original Filed Feb. 11, 1964 4 Sheets-SheetINVENT OR 'RQBEQT SBQKE ma wmgfmww ATTORNEYS f s Q Jan. 2, 1968 R. s.BAKER 3,361,020

CABLE-(BUTT ING APPARATUS Original Filed Feb. 11, 1964 4 Sheets-Sheet 4INVENTOR ROBERT S. Bm ER mailk iwicsw will ma ATTORNEYS United StatesPatent 3,361,020 CABLE-CUTTING APPARATUS Robert S. Baker, Tampa, Fla.,assignor to American Concrete Crosstie Corporation, Tampa, a corporationof Florida Original application Feb. 11, 1964, Ser. No. 344,095, nowPatent No. 3,305,907, dated Feb. 28, 1967. Divided and this applicationFeb. 27, 1967, Ser. No. 618,742

6 Claims. (Cl. 83-214) ABSTRACT OF THE DISCLOSURE Cable-cuttingapparatus which utilizes spaced power saws, each vertically slidable,with a control system including a counter, the counter being operable inresponse to saw motor load to cause sequential movement of the saws intocutting position.

Cross-reference to related application This application is a division ofco-pending application of Robert S. Baker, Serial No. 344,095, filedFeb. 11, 1964, now Patent No. 3,305,907, for Machine for MakingPrestressed Concrete Members.

Background of the invention This invention relates to apparatus forcutting the cables of prestressed concrete members to free the membersfrom their molding pallets after the concrete members are cured, andparticularly to such apparatus for use in connection with machines forautomatically making prestressed concrete articles.

In the above mentioned co-pending application, a machine is disclosedfor automatically making prestressed concrete members. The machineincludes a platform along which pallets are advanced to stations forinserting stressing cables in the pallets and anchoring them therein,for stressing the cables, for pouring and molding the concrete member,for transferring the molded member on its pallet to a transporting carfor passage through a curing tunnel, for loading the cured pallet backonto the platform, for cutting the cables to free the cured member fromthe pallet, and for removing the cured member from the pallet. Theoperation is continuous and automatic.

The present invention is concerned only with the apparatus for cuttingthe stressing cables to free the concrete member from its connection tothe pallet. Reference may be had to the co-pending application for acomplete disclosure of the machine for forming prestressed concretemembers.

Summary of the invention The principal object of the present inventionis to provide means for cutting stressing cables which are embedded in aconcrete member and anchored to a pallet to release the tension of thecables to the concrete member, and to free the member from the pallet sothat it can be removed.

Another object of the invention is to provide means to cut cables at theopposite ends of a prestressed concrete member in such manner that therewill be no possibility of the concrete member jumping to one end of thepallet and jamming the saw at that end.

A still further object of the invention is to provide cable-cuttingapparatus which will cut several cables sequentially at one end of aprestressed concrete member, then cut the cables sequentially at theopposite end of the concrete member. 1

Yet another object of the invention is to provide cable- 3,361,020Patented Jan. 2, 1968 cutting apparatus wherein motor load is used as acontrol for the cutting operation.

Other objects of the invention will become apparent from the followingdescription of one practical embodiment thereof, when taken inconjunction with the drawings which accompany, and form part of, thisspecification.

Brief description of the drawings Description of the preferredembodiment Referring first to FIGURE 1, there is shown diagrammaticallya plan of the entire apparatus with which the cable-cutting mechanism ofthe present invention is particularly designed for use. It consists of arectangular orbit, or path, 1 for a pallet transporting means. Thetransporting path includes a leg 2 along and above which a concretemember forming machine 3 is located, and a parallel leg 4 substantiallythe whole length of which is enclosed by a curing tunnel 5. Connectingthe ends of the legs 2 and 4, and completing the orbit are transfer pits6 and 7 along which transporting cars 8 are shifted from the formingmachine leg 2 of the orbit to the tunnel leg 4, and from the tunnel legto the forming machine leg.

The concrete member forming machine has a base 9 ;forming a bridge overthe leg 2 of the transport path, and

a platform upon which various stations, where the several requiredoperations are performed, are located. These include (starting at theright end of the machine as shown in FIGURE 1) a pallet receivingstation 10, the cable cutting station 11, a concrete member removalstation 12, a pallet header cleaning station 13, a pallet cleaningstation 14, an anchor inserting station 15, a cable laying station 16, acable stressing station 17, a molding and vibrating station 18, and aloaded pallet delivery station 19.

The base 9 is formed of a tending, horizontally spaced, vertical wallsor legs 20, with a flat platform 21 resting upon the tops of the legs.The legs, and the portion of the platform which bridges the legs, formsa tunnel 22 through which the transporting kiln cars 8 move. Theplatform is sufficiently broad to project some distance beyond the legson either side of the tunnel. It is upon this platform that the variousoperating stations, including the cable-cutting station, are mounted.

Pallet tracks 23 are mounted on the platform 21, and extend the fulllength of the platform. The track, and the means for moving palletsalong the track, can be any appropriate type, and one specific track andpallet moving means is described in detail in the above mentioned 00-pending application.

The pallet 24, in which the concrete member is formed, and which forms atransporting receptacle for the member, is an elongated, trough-shapedmember having a fiat bottom 25 and upwardly diverging side walls 26. Theends are formed by headers 27 and 28 which span the ends of thetrough-shaped member. Header 27 is rigidly fixed to the trough end,While header 28 is a movable one having no permanent connection to thetrough. The movable header is moved outwardly and held in its movedpopair of longitudinally exsition to stress the cables as described indetail in the co-pending application. Each header has a plurality ofcable openings 29, and a cable anchor is attached to the header inalignment with each of the openings. When the cables are inserted in theopenings they will be held by the anchors during stressing andthroughout the concrete member forming and curing operations. Althoughthe cable openings may have any desired pattern, each header is shown ashaving four openings as seen in FIGURE 2.

After the concrete members are formed on the pallets, they are moved to,and through, the curing tunnel 5 and then transferred back to themachine leg of the apparatus. The pallets, with the cured concretemembers, are unloaded from the cars and onto the pallet track at thepallet receiving station, and then moved along the pallet track untilthey arrive at the cable-cutting station 11. Here, the cables 31 are cutfree from the headers, so that the cable tension is released to thecured concrete member, and the member is free to be removed from thepallet.

At the cable-cutting station, there is a frame 32 supported upon themachine platform 21. The frame includes a standard 33 at one side of thepallet track 23, and a standard 34 at the other side. The two standardsare connected at their tops by a bridge beam 35 which extends across thepallet track. Standard 33 is composed of two legs 36, spaced aparttransversely of the machine platform and interconnected by verticallyspaced, horizontal base plates 37. One of the plates is at the tops ofthe legs and the other is at a level below the tops of pallets on thepallet track. Brackets 38 are mounted at the ends of the base plates andform supports for vertical guide rods 39. Rods 39 slidably receivebushings 40 at the rear of a saw motor bed 41. A saw motor 42 is fixedto the bed, and carries an abrasive saw 43 upon its shaft 44. Thevertical plane of the saw will pass through the exposed cables betweenthe end of the cast members and the pallet headers of pallets on thepallet track. The exposed cables span the spaces at the pallet endsoccupied by the mold box ends during the casting operation. A cylinderassembly 45 has its cylinder 46 mounted upon the upper base plate 37,and its piston rod 47 fixed to the motor bed 41. Operation of thecylinder will cause the bed to lower and rise on the guide rods 39.

Standard 34 is identical to standard 33 and has a similar motor and sawmounted upon it. The parts of the standard and saw are given the samereference numerals with a prime afiixed.

It is necessary in operating the cable-cutting saws to cut the cables atone side of the pallet and then those at the other side. This willprevent jamming and breaking the saws in the event one saw should cutthrough the cables before the other, thus allowing the concrete memberto jump to the opposite side of the cable tension. Therefore, it isdseirable to cut through the upper cables at one side, then the lowerones, and then repeat this procedure on the opposite side.

The controls to accomplish the above stated operation are timed from acam shaft 48 by means of a cam 49. The cam has a notch 50 into whichswitch arm 51 will fall to start operation of the saw cycle.

The saw motors 42 and 42 are connected to heavy duty power lines of thesystem. A common wire 52 of the motor circuits is connected to theprimary winding of a transformer 53. The motors run continuously duringmachine operation, and increases in motor load will cause the motors todraw more current, and therefore increase the current induced in thesecondary winding of the transformer 53. This permits motor load to beused to control the cutting operation as will be described.

The step-by-step operation of the motors is achieved by means of a stepcounter 54 which has a hand 55, a series of counter contacts 56, acounter coil 57 and a release coil 58. The counter coil is energizedupon increases in load on the motors to cause the hand to movestep-by-step, and the release coil is energized by closing switch 51 byrotation of cam 49. Switch 51 is connected to power line 59 by line 60,and to release coil 58 by line 61. The opposite side of coil 58 isconnected to a return line 62 by line 63. Therefore, closing switch 51will energize coil 57 and cause counter hand 55 to move back to the No.1 contact of the series 56. This will complete a circuit from powersource 59 through line 64 to solenoid coil 65, controlling the operationof cylinder assembly 45 to start the saw 43 moving downwardly toward thepallet. A line 66 connects the coil 65 with contacts No. 1 and No. 2 ofthe counter. As the counter hand is at contact No. 1, the circuit iscompleted through the hand and line 67 to line 62.

The saw assembly will continue its downward movement until saw 43contacts the top pair of cables. Cutting of the cables will increase themotor load and the current induced by the transformer 53 will varydepending upon whether the saw is cutting or running free. Thetransformer secondary winding is connected by wire 68 with a relay coil69. When the induced current in the transformer reaches a predeterminedamount, relay 69 will operate to close its contacts 70, thereby closinga circuit through the coil of a control relay 71. This circuit is fromwire 59, through wire 64, wire 72, contacts 70, wire 73, coil of relay71, and wire 74 to return wire 62. When the coil of relay 71 isenergized, a capacitor 75 discharges through a circuit including thecounter coil 57 to cause the counter hand 55 to move from the No. 1 tothe No. 2 contact of the series 56. As these two contacts are includedin the circuit through coil 65, the saw 43 will continue downwardly tocontact and cut the next two cables. The capacitor is connected acrossthe lines 59 and 62 through a rectifier bridge 76 by means of wires 77and 78 through the normally closed contacts 79, to provide forunidirectional flow through the capacitor during its charging anddischargeing periods. The branch lines 80 and 81 connect the capacitorto the counter coil 57 through the normally open contacts 82 of relay 71when the relay is energized.

It will be clear from the above that the saws have a stepped movement.Saw 43 first moves down to cut the top cables at its side of the pallet.The load fluctuation on the saw motor causes the counter to move fromthe No. 1 to the No. 2 contact when the top cables are cut. The saw willmove down and cut the second cables. The counter will operate againmoving the hand to the No. 3 contact. This accomplishes two things: thecircuit through coil 65 is broken and the valve of cylinder assembly 45will shift automatically to lift the saw 43 to inoperative position; anda parallel circuit through a solenoid 83 will be made to start saw 43'on its downward movement. The movement of saw 43 is a two-step one also,with the contacts No. 3 and No. 4 of the counter being connected to thewire 84 through the coil 83 circuit. When saw 43' cuts through the lowercables at its side of the pallet, the counter hand will move to the No.5 contact breaking the circuit through coil 83 and permitting the saw torise. When cam 49 completes its revolution, switch arm 51 will drop intonotch 50, closing the circuit through release coil 58 to return thecounter hand to the No. 1 contact of the counter to restart the cycle.

With the above described control system, the saws will be operated inalternation so that the cables at one end of the cured tie will be outprior to the lowering of the other saw into cutting position. Thus, ifthe tie should jump lengthwise in the pallet after the cables have beencut, there will be no saw blade in the opposite end of the pallet tobecome jammed or broken by the impact.

While in the above, one practical embodiment of the invention has beendisclosed, it will be apparent that the details of structure shown anddescribed are merely for purposes of illustration and the invention maytake other forms within the scope of the appended claims.

I claim:

1. In apparatus for making prestressed concrete members in palletshaving stressing cables anchored in the ends thereof, means for cuttingthe cables to free the cables from pallets at a pallet position afterthe concrete members are cured comprising, a pair of saws located abovethe ends of pallets at the pallet position and movable into the palletsto cut the cables adjacent the cable ends.

2. In apparatus for making prestressed concrete members in pallets asclaimed in claim 1 wherein, there is means to move the saws into palletsin sequence, the saw moving means being operative by cutting action ofthe first-lowered saw to raise the first lowered saw and lower the othersaw.

3. In apparatus for making prestressed concrete mem bers in pallets asclaimed in claim 1 wherein, there is means to move the saws into thepallets in sequence, the means including a counter operative uponcompletion of a predetermined number of cuts by a first lowered saw tocause the first lowered saw to move out of the pallet and the other sawto move into the pallet.

4. Apparatus for cutting cable ends at opposite ends of a prestressedconcrete member comprising, a frame to straddle a prestressed member,vertical guides on the frame at opposite sides thereof, saw assembliesslidably 25 mounted on the guides, means to raise and lower the sawassemblies, and control means to operate the means to raise and lowerthe saws to act in sequence to cause the saw assemblies to move to andfrom cutting position in alternation.

5. Apparatus for cutting cable ends at opposite ends of a prestressedconcrete member as claimed in claim 4 wherein, the means to operate themeans to raise and lower the saw assemblies includes a counter operativeupon completion of a predetermined number of cuts by a first lowered sawassembly to cause the first lowered saw assembly to raise and the othersaw assembly to lower.

6. Apparatus for cutting cable ends at opposite ends of a prestressedconcrete member as claimed in claim 5 wherein, the load on the sawassemblies during cutting actuates the counter.

References Cited UNITED STATES PATENTS 3,217,375 11/1965 Kinnard 1l83,223,379 12/1965 Erickson 25-118 WILLIAM S. LAWSON, Primary Examiner.

9/1962 Gerwick 25--l18

